Various types of systems have been developed that support communication carried out among users through message exchange using information communications technologies. Group call of cellular phone systems, chat systems, and intercom systems, for example, are known particularly as systems that enable conversation among member users of a group.
To allow member users of a group to converse with each other, a group is first formed to contain the member users who participate in a conversation. In this process, known systems require a first member user who wants to initiate a conversation to perform troublesome operations, including sending a participation request to a specifically designated second member user whom the first user wants to participate in the conversation and specifying requirements of the member user for the participation in the conversation. The second member user, in this case, may often find it difficult to determine whether to accept the participation request when not knowing the theme of the conversation. Therefore, there is a need for an arrangement that allows a participation request together with information on the theme of the conversation to be made through a simple operation to achieve conversation among specific member users.